Regensburg 2025 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 17: Development of Calculation Methods

MM 17.5: Vortrag

Mittwoch, 19. März 2025, 11:15–11:30, H22

Accurate TDDFT Excited-State Spectra Across the Full Spectral Range — •Matthias Kick and Troy Van Voorhis — Massachusetts Institute of Technology, Cambridge, MA, USA

Theoretically, electronic excitations can be obtained by analyzing the frequency components of the time-dependent dipole moment obtained from real-time time-dependent density functional theory (RT-TDDFT) simulations. Yet, an exact treatment of electronic excitations in large systems with TDDFT is computational prohibitive. Super-resolution techniques such as compressed sensing typically fail due to the presence of a quasi-continuum of electronic excitations. We present a new approach where we combine exact short-time dynamics with approximate frequency space methods. As a prototypical test system, we use an organic dye-molecule adsorbed on a semi-conductor quantum-dot surface. We calculate the entire electronic absorption spectrum of this system and find that our approach can accurately capture narrow features and a quasi-continuum of states at the same time. We see a reduction of the required amount of data points up to a factor of 20 compared to standard Fourier analysis. By doing so, our method allows us to study electronic properties of large systems in ways that are not currently possible.

Keywords: Electronic structure; Super-resolution; Excited states